beyond the pale

Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

Describing behaviour that is considered to be outside the bounds of morality, good behaviour or judgement in civilised company.

from the GNU version of the Collaborative International Dictionary of English

n. outside the limits of what is allowed or proper; also, outside the limits within which one is protected.

Etymologies

from Wiktionary, Creative Commons Attribution/Share-Alike License

From pale, a jurisdiction under a given authority; often held by one nation in another country, hence suggesting that anything outside their control was uncivilised. It was in use by the mid-17th century. The phrase may be a reference to the general sense of boundary, but is often understood to refer to the English Pale in Ireland. In the nominally English territory of Ireland, only the pale fell genuinely under the authority of English law, hence the terms within the pale and beyond the pale.